Development and Initial Validation of Quality-of-Life Questionnaires for Intermittent Exotropia
Presented in part at: Association for Vision and Research in Ophthalmology Annual Meeting, May 2009, Fort Lauderdale, Florida.
Received 20 February 2009; received in revised form 15 June 2009; accepted 19 June 2009. published online 06 November 2009.
Purpose
The development and initial validation of patient-derived, health-related quality-of-life (HRQOL) questionnaires for intermittent exotropia (IXT).
Design
Cross-sectional study.
Participants
In a development phase, 27 children (age, 2–17 years) with IXT and 1 of their parents. In an initial validation phase, 33 children with IXT and 49 control children (age, 5–17 years), along with 1 parent for each child. Children in the control group had no strabismus or amblyopia.
Methods
Individual patient interviews generated 35 items for child and proxy (parental assessment of child's HRQOL) questionnaires and 46 items for a parent questionnaire. To reduce to a feasible number of items, questionnaires were administered to 5- to 17-year-old children with IXT (n = 15) and parents of 2- to 17-year-old children with IXT (n = 27). Responses were analyzed using standard item reduction methodology. Three final derived IXT questionnaires (IXTQ): child, proxy, and parent (12, 12, and 17 items, respectively) were administered to children with IXT and control children and to parents of IXT and control children. Likert-type scales ranging from never (100, best HRQOL) to almost always (0, worst HRQOL) were used.
Main Outcome Measures
Median scores for IXT and control groups, compared using Wilcoxon tests.
Results
Median child scores were significantly lower (worse HRQOL) in the IXT group compared with the control group: 85 (quartiles, 73–92) versus 92 (quartiles, 79–96; P = 0.04). Median proxy IXTQ scores were significantly lower for IXT children than controls: 83 (quartiles, 75–94) versus 98 (quartiles, 92–100; P<0.0001). Median parent IXTQ scores also were significantly lower in the IXT group compared with the control group: 68 (quartiles, 56–79) versus 93 (quartiles, 87–99; P<0.0001).
Conclusions
A new 3-part patient-derived HRQOL questionnaire for children with IXT and their parents has been developed and validated, comprising child, proxy, and parent questionnaires. These questionnaires detect reduced HRQOL in children with IXT as reported by the children themselves and perceived by their parents (proxy report). Childhood IXT also seems to affect parent HRQOL. The IXTQ HRQOL questionnaires may prove useful in the clinical assessment of IXT and for clinical trials.
Financial Disclosure(s)
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Available online: November 6, 2009.
1Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota
2Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina
Correspondence: Jonathan M. Holmes, BM, BCh, Ophthalmology W7, Mayo Clinic, Rochester, MN 55905
Manuscript no. 2009-248.
Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Supported by the National Institutes of Health, Bethesda, Maryland (grant nos.: EY015799 [JMH], EY018810 [JMH], and EY013844 [EAB]); Research to Prevent Blindness, Inc., New York, New York (JMH as Olga Keith Weiss Scholar and an unrestricted grant to the Department of Ophthalmology, Mayo Clinic); and the Mayo Foundation, Rochester, Minnesota. None of the sponsors or funding organizations had a role in the design or conduct of this research.
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